Brewing machines for brewing coffee are well known. One well known brewing machine, which is disclosed in U.S. Pat. No. 5,325,765, is configured to receive a cartridge that contains a mass of brewable substance such as coffee. The cartridge includes a fluid impermeable cup made from a flexible plastic inside of which a filter is disposed. The filter, which is shaped like a cup or a cone, is directly joined to the interior wall of the cup at the top edge of the cup, which defines the mouth of the cup. The brewable substance is deposited inside the filter and the mouth of the cup is closed with a metal foil, which is joined to a radially extending flange residing at the mouth of the cup.
To brew the brewable substance, the machine disclosed in U.S. Pat. No. 5,325,765 is configured to inject hot water into the cartridge with a means that pierces the foil. Exposure to the hot water so injected for a short period of time brews the substance inside the cartridge to produce a brewed beverage (e.g. coffee). The brewed beverage passes through the filter and is deposited at the bottom of the cup. Thereafter, the machine disclosed in U.S. Pat. No. 5,325,765 pierces the bottom of the cup allowing the brewed beverage to exit.
Keurig, Inc., the assignee of U.S. Pat. No. 5,325,765, markets a machine according to U.S. Pat. No. 5,325,765 as well as cartridges for use with that machine. U.S. Pat. No. 5,840,189, also assigned to Keurig, Inc., discloses a cartridge for use with the machine disclosed in U.S. Pat. No. 5,325,765.
The cartridges marketed by Keurig, Inc. for use with the Keurig machines are slightly different in configuration than the cartridges disclosed in U.S. Pat. No. 5,840,189. FIG. 1 illustrates a cross-sectional view of a cartridge 10 marketed by Keurig, Inc. Referring to FIG. 1, cup 12 of cartridge 10 includes a frustoconical bottom portion 14 having a closed bottom 16 and an open top 18 defined by a top edge 19. An endless, annular wall 20, which may be cylindrical, is joined at its bottom edge 22 to edge 19 of frustoconical bottom portion 14 via an intermediate, endless, annular, flange portion 24. Intermediate flange portion 24 extends radially away from the interior of frustoconical bottom portion 14 and surrounds top edge 19 of frustoconical bottom portion 14 and its top edge 19. Wall 20 terminates at a top edge 21, which defines the open mouth of cup 12. Top edge 21 is joined with a top flange 26 that extends away from the interior of wall 20 in a radial direction. Foil 28 is joined with top flange 26. A cup shaped filter 30 extends from top edge 21 of wall 20 to a depth less than the depth of cup 12, whereby bottom 31 of filter 30 is spaced from closed bottom 16 of cup 12. A portion of filter 30 extending from its top edge 33 is directly joined to an interior surface of wall 20 as illustrated in FIG. 1.